Pregnancy induced hypertension (high blood pressure)

Blood pressure is the amount of force exerted by the blood against the walls of your arteries as it flows through the blood vessels. Your blood pressure is considered high when the readings are greater than 140 mm Hg systolic (the top number in the blood pressure reading) or 90 mm Hg diastolic (the bottom number). In general, high blood pressure, or hypertension, contributes to the development of coronary heart disease, stroke, heart failure and kidney disease.

Hypertension (high blood pressure) that occurs during preg­nancy is called pregnancy-induced hypertension (PIH). Most women who develop PIH did not have hypertension before preg­nancy and will not have it after. PIE was formerly known as toxaemia. While the cause of PIH is unknown, some studies sug­gest that the blame lies with an imbalance of the substances that regulate the constriction and dilation of the blood vessels. The risk factors include heredity, a diet low in protein or calcium, a history of preeclampsia prior to 32 weeks gestation, chronic high blood pressure, kidney disease, lupus, diabetes, multiple pregnancy, age (under 20 or over 35) and being overweight. A new theory states that PIE may be an immune response to a new sex partner, since 85 percent of cases occur in first-time pregnancies. Several studies have shown that a good diet can reduce the risk of developing PIH. A diet containing 75 to 100 grams of protein and 1,500 to 2,000 milligrams of calcium is recommended.

PIH affects both the woman and the fetus. High blood pressure constricts the blood flow to the uterus. This can result in the baby receiving less oxygen and nutrients, which will affect his growth. In addition, the placenta may separate from the wall of the uterus before delivery and result in bleeding and shock. If untreated, PIH can become preeclampsia, which is characterized by high blood pressure, protein in the urine, sudden weight gain and swelling of the face and hands. It may be necessary to induce labour if the blood pressure is not controlled. This may lead to a premature infant. Rarely, preeclampsia progresses to eclampsia, which is marked by convulsions, coma or even death of the woman or baby.

Treatment of PIH consists of bed rest for mild conditions. Occasionally, a woman must be hospitalized. If the blood pressure is not controlled, delivery by induction of labour or cesarean sec­tion may be necessary to save the lives of the woman and baby. The medication magnesium sulfate is administered intravenously to prevent convulsions. The risk of seizures diminishes 48 hours after delivery of the baby.